Question: Is there a source in the Torah that expounds on the idea that “Fear can blind a person. So much so that the person can’t think and his clarity is gone”- or is that a bogus theory?
Answer: While the Talmud does speak of different types of fear that can have different effects on a person, I think it is very reasonable to assume that most fear – especially fear that leads to panic – will weaken a person’s ability to reason.
The clearest Torah source for this that I could think of off-hand is in Lev. 26:36:
And to those of you left over I will send fear into their hearts in the lands of their enemies, and the sound of a blown leaf will cause them to flee, as from the sword will they flee and they will fall (despite there being) no pursuer.
Lev. 26:16 and Deut. 28:28-9 and 28:34 seem relevant too. Now, how to fight back and reclaim ones clarity of mind despite fear (or how to attack the fear itself) is, of course, a much bigger topic…
I hope this helps,
Rabbi Boruch Clinton